Spiral track developing tank



Jan. 16, 1951 Filed May 18, 1945 V. E. PRATT ET AL SPIRAL TRACK DEVELOPING TANK 2 Sheets-Sheet INVENTOR. VERNEUR E. PRA 77 BY GEORGE F. GRAY ATTORNEYS 1951' v. E. PRATT ETHAL SPIRAL TRACK DEVELOPING TANK 2 Sheets-Sheet 2 Filed May 18 194$ e w Q Q MT 4 7 3 A d f OM w A A A A A 8 2, A M. M A

4 w J 6 4/A 0 N 0 w' 3 l m m 4 Z I/ERNEUR E. PRA 77' A TTO/QNEVS Patented Jan. 16, 1951 Verneur E. Pratt andGeorge- F. Gray, .N'orwalk, Conn.

Application May" 18, 1945', Serial N'o. 594,506

2 Claims.

This invention relates to: spiral track developingtanks: of the type used for developing, fixing.

and washing strips of film. Such. tanks. comprise a. tank or receptacle in. which there. are members or plates spaced apart and having; spiral grooves in their opposed surfaces in which the film is wound. These forma spiral track for the film whereby it; is coiled. within the carrier formed. by the; plates and with its convolutions spaced apart. While, liquids; can be poured intosuch tanks in the. daylight the film must: be. inserted in the carrier: inthe dark room or in dim. light depending. on. the. sensitivity of the emulsion. In tanks using; known. forms: of: carriers the; user.- must push or lay the film into the spiral grooves in. the plates, working in the dark.

r In some models the carrier comprises a pair of plates carried one central shaft which positions the plates with their opposed. grooves properly spaced, to receivevthe film. A. hook is furnished on the. central. shaft to, which the inner end of. the film canbe. afiixed, in order that the user can, then lay the film inthe grooves but in most ofv the tanks; thelcng, limber length of film must be pushed into; the grooves.

. Pushing the film. into the grooves is difficult enough whenthe tank is new andthe; grooves are dry and. clean; itbecomes more; difiicultand often impossible when the grooves becomecovered with theprod'ucts of deyelopment randaare. abrasively coated. with. silver deposit, or; when the grooves are not completely dried and the surface tension of the; waterleft in the; grooves-facts. to retard the. insertion of the film.

On the types of spirals-wound tanks. which pre- 1 some that the user will lay the film in the grooves, it has: beenfound that even after muchpractice in the; dark, the average user makes, mistakes and too often. the successive layers; of; film. are: not. adequately separated. in; the. grooves, with the result; that the film touches} and developing: and fixing: are incomplete to the. extent that too often the images are lost.v

An object; of. the instant invention. is tofurnish a spiral track carrier into the. grooves: on. which. the; film. is pulledrather: thanpu shed or) laid.

Another object; is. to; providella carrier of; the type described. in. which the. film. can be; pulled, which is adjustable; to. take film. of; various widths.

Another object, is to provideja film carrier of the type. described inv which the; may be: pulled into the groove when. the. same; are. wet and: where a. considerable: length. of film; can be pulled: into; the. grooves with'ease. regardless of Other objects: of the invention will be apparent from. an, examination of the. following specificartion and: drawings In the accompanyingdrawings:

Figure 1 is a vertical view partly in section of the feed fingers and one of the plates of a film carrier embodying. this invention and taken. on the. line: l.-l. of Figure 2;

Figure: 2 is. a vertical sectional view of a film carrier embodying the invention; 1-

Figure; 3 is a view on. the line 3,. 3, Figure 1 looking down. on. the shaft. [4 shown. in. Figures 1. and 2. and showing: the parts. and 30: insection;

Figure 4 is a front view of the device shown in the preceding figures with one: of its feed fingers 30- in extended position;

Figure 5 is an enlarged rear view of the. feed fingers 24 and 30:

Figure 6- is a slightly enlarged. sectional view on the line; 6--6 of Figure 5;

Figure 7 is a view partly in section on. the line 1 loft Figure 8 showing an alternate type of'feed finger but, showing both plates l0 and ll of the device;

Figure 8 is a view partly in section on. the line 8-8 of Figure; 7"

Referring to Figures 1 and 2, the nmnerals l*'fl--l2l indicate the usual pair; of: plates; used in film carriers having therein. respectively the con:- tinuousv spiral grooves i'2- l'3.; these. grooves begin as shown: for the groove 13' at l3'b', on the outer periphery of the plates and, continue. inwardly to a point adjacent the shaft I'd.

The. shaft M together with its: knob. and nuts is usually sufficient to hold the plates together without. wobble when assembled as hereinafter described. But; in order to prevent the plates from having any'relative turning movement the plate l0 may be equipped with three pins: one of which is shown at 15: which fit corresponding holes in plate- H; This arrangement permits the: plates: to be. separated laterally to take of difierent widths but does not allow the plates to revolve around the shaft" M independently of each other.

Permanently secured to the: shafit- M is; the

knob is... The shaft extends; inwardly through a bearing 1;! in plate [ii and then across, a space. [8 between the inner surface of the plates: From the inner surface of plate H and outwardly therefrom. the: shaft; l4 threaded as? shown at LG. this: threaded portion. is placed a, nut 20 which may be turned. to; vary the of the space; I8. and consequently permit the processing: of. film of: differentwidths. A look. nut

2| engages the external threads on nut and an additional lock nut 22 may be brought up against the outer end of 20 as shown so that all three nuts 20, 2| and 22 are locked to the shaft l4 so as to revolve therewith. It will be seen that this shaft can be turned while the plates l0 and II are held stationary and properly spaced apart thereon.

The shaft l4 has a square hole 23 therein adapted to receive the feed finger 24 which is freely slidable in this hole. tends upwardly, the upper end of same as shown in Figure 2 having an L-shaped extension 25 thereon which extends into the spiral groove [3 in plate Hi. This extension 25 has a small up- This feed finger exstanding lip 26 adapted to provide a seat or space between the inner edge 21 of the groove l3 and the film 28.

In the upper end of the feed finger 24 is-provided one or more teeth 29 which project forward at an angle in the direction of the travel of the feed finger as best seen in Figure 1 and which are adapted to catch and hold the'end of the film 28 when the finger is moved clockwise, Figure 1.

Now by engaging the film 28 on these teeth and rotating the knob It; to rotate the finger 24 between the plates, the film 28 may be drawn into the grooves 52 and I3. As this occurs the end 25 of the feed finger 24 gradually progresses inwardly toward the shaft Hi, the feed finger .24 sliding through the opening 23 therein. The film 28 is therefor pulled into the grooves l2 and 33 without any care or attention on the part of the operator and is coiled between the plates with its convolutions held apart by the grooves therein.

It will be understood that the total diameter of the device is such that'ample room is provided between the last or inner convolutions of the grooves indicated at Na in Figure 2, so that the inner end of the finger 24 in the space l8 will have room in which to travel without encountering any film that has been drawn into the device.

It will be observed that the right hand edge 28a of the film 28; Figure 2, extends to the right out beyond the edge 24a, of the feed finger 24, but this is not found to be objectionable as the film is laterally quite stiff and if guided into the left hand roove l3 it is stiff enough to guide itself properly in the right hand groove l2.-

Where the film is. comparatively wide or very thin, it may be necessary to guide the right hand edge 28a just referred to. the auxiliary feed finger 30 is provided. This finger 3!] lies in a sunken or cut out pocket 3| on the rear side of the feed finger 24.

For 16 mm. or other comparatively narrow film the auxiliary'feed finger is placed with its short end 3811 projecting to the right as shown in Figure 2, this end having the upstanding lip 3% corresponding to the lip 26, the film being positioned between thelips as shown... The auxiliary finger is secured in the pocket 3! of -.the finger 24 by means OfIaSClBWLSZ'." 1 l In order to provide for the'u'setof wider film the auxiliary feed finger 30 may be turned'so that the long arm 38d thereof will'proj'ect to the right. This has upstanding lip 3110 same as the lip 26 previously described and may be equipped with a plurality of .teeth .35) for the purpose of engaging and holding thefilm; ..j

Obviously when the auxiliary-feed Ifinger is usedthe plates l0. and II. are sep'aratedthe To .accomplish this 4 necessary distance which is accomplished by adjusting the nuts 20, 2|, 22 on shaft [4 as previously described.

It will be seen that the auxiliary feed finger 30 has two positions in which it may lie in the cavity 3|. In one position the short arm 30a extends outwardly from finger 24, and in the other position the long arm 30d extends outwardly therefrom, and by means of the screw 32 the auxiliary finger may be locked to the feed finger 24 in either position.

As shown in Figure 6 the auxiliary finger 3!] lies in'the cavity 3| and there is an upstanding wall 24a along one of the outer edges of 24, the arrangement being such that when the feed fingers have been pulled inwardly, that both said fingers will ride through the square opening 23 in the shaft 14 as best seen in the sectional view Figure 3.

As is customary with these film carriers, the plates I 0 and l i andthe shaft [4 may have holes or slots therein to'permit the free circulation'rof liquid around and about the film in all dir'ec: tions in order to enable the liquids to reach all of the film simultaneously thereby preventing spotty development etc. I

Instead of the feed finger arrangement pre-' viously described any other suitable arrangement can be used for pulling the film into the slots. Such an arrangement is shown in Figure'7.' A spring member-33 is secured tothe upper end of the feed finger 34 which is the same as the feed finger 24 of Figure 3 except that it tapers off to a comparatively narrow width at the top as indicated at 34c Figure 3 and is embraced bythe inner U-shaped bend 33a of the member 33 which is secured thereto by means of a screw 35. The upper end 34a of the feed finger has claws 36 to engage the film 31.

As the member 33 is resilient the outwardly extending jaws that ride in the grooves I 2, I3 being sprung outwardly, the plates in, II can be brought together or spaced apart and the outer ends of member 33 will continue to ride in the grooves in these plates and guide the feed'finger and film in thegrooves as previously described.

The operation of the device is of course' the same regardless of what type of feed finger is used therein. It is believed that theoperation of ithe'device will be self-evident from the foregoingde'scription,but it may be pointed outthat the side 10 having the shaft l4 therein, may be laid upon"a table in the dark room, andthe end of the film 28 may be brought in through the mouths such as l3b of the groove l3 and impaled on the teeth 29 of the feed finger. The side plate H is now slipped-over the pins l5 and is brought against the nut 20 which has been suitably adjusted along. the threaded shank !9 of the shank I l to provide aproper space at 3 for the film being used. After the side plate H is placed in position, the nut 2| is placed against the nut 20 and the locking nut 22 is placed in position as best shoWninF'igureZ.

' If no'wlthe device is held inlone hand and shaft 1411's rotated with the other, the film 28 will be g'r'adually' drawn 'into the continuous spiral grooves l2, I 3'; and willbe held between the side' plates to and H in a spiral form having its sensitive surfaces spaced apart by reason of the manner in .Which it isfheld. It will alsoibe'seen that as the inner end of the feed finger: 24 moves through the opening 23 in shaft l4, that by.'properlyproportioning the distance between the inner-most turn of the spiral groove and the shaft, that the said inner end of the member 24 will not encounter the inner convolution of the film, or in fact, touch the film in any way.

It will also be observed that adjustments necessary to accommodate various Widths of film can be made before the device is'taken into the dark room, and that the only manipulation of the device in the dark room is to place the starting end of the film on to the teeth of the feed finger, then bring the plates II], II together, and finally tighten the nuts 2!, 22 finger-tight.

What is claimed is:

1. In a device of the character described, members having complementary spiral grooves on their opposed faces when held in spaced-apart relation, a shaft passing through said members and revolvable therein, said members being adjustable along said shaft to vary the distance between their opposed faces, means for locking said members in the desired adjusted position, a feed finger slidable through said shaft and supported thereby, and engaging at least one of said grooves whereby said finger will be guided in said groove when said shaft is revolved in said members, said finger being adjustable to span the distance between said members, and means on said finger to engage and carry film into said grooves when said members and shaft are relatively moved.

2. In a device of the character described, means including Opposed members forming a spiral track therebetween adapted to receive and hold a film by its edges, said members being axially adjustable to vary the distance between them, a shaft positioned adjacent the inner end of said track, and a feed finger slidably engaging said shaft and track and adapted to feed film into said track upon relative movement of said track and finger, said feed finger being adjustable to span the distance between said opposed members.

VERNEUR E. PRATT. GEORGE F. GRAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

